An electrochemical fuel cell is a device that converts fuel and oxidant to electricity, reaction product, and heat. Fuel cells commonly are configured to convert oxygen and a proton source, such as hydrogen, into water and electricity. In such fuel cells, the hydrogen is the fuel, the oxygen is the oxidant, and the water is the reaction product.
The amount of electricity produced by a single fuel cell may be supplemented by connecting two or more fuel cells together. A plurality of connected fuel cells is commonly referred to as a fuel cell stack. The fuel cells in a fuel cell stack are typically connected in series. Fuel cell stacks may be incorporated into a fuel cell system, which generally includes a source of hydrogen gas or other fuel for the fuel cell stack, and which typically also includes other components adapted to facilitate the conversion of fuel and oxidant into electricity.